Device for cutting a rolled medium

ABSTRACT

In a copying apparatus or the like using a rolled medium, a device for cutting the rolled medium into a predetermined length comprises cutter means, cutter operating means, rolled medium conveyor means and a conveying path both provided rearwardly of the cutter means. The device further includes second detector means operated by the rolled medium when a predetermined time T2 has elapsed after cutting, and first detector means operated when a time T1 determined by the length of the medium cut off has elapsed after the cutting. The first and second detector means are located so as to satisfy the relation that T3&gt; T1&gt; T2, where T3 is the time required for one cycle of operation. The cutter means is operated to effect an additional cutting operation when the first detector means properly operates but the second detector means does not do so.

United States Patent [191 Katayama et a1.

[ DEVICE FOR CUTTING A ROLLED MEDIUM [75] Inventors: Hajime Katayama;Yoshimasa Kimura, both of Tokyo, Japan [73] Assignee: Canon KabushikeKaisha, Tokyo,

Japan 221 Filed: Dec. 22, 1972 21 Appl. No.: 317,781

[30] Foreign Application Priority Data [11] 3,817,134 June 18, 1974Primary Examiner-J. M. Meister Attorney, Agent, or FirmFitzpatrick,Cella, Harper & Scinto 5 7 ABSTRACT In a copying apparatus or the likeusing 3 rolled medium, a device for cutting the rolled medium into apredetermined length comprises cutter means, cutter operating means,rolled medium conveyor means and a conveying path both providedrearwardly of the cutter means. The device further includes seconddetector means operated by the rolled medium when a predetermined time Thas elapsed after cutting, and first detector means operated when a timeT determined by the length of the medium cut off has elapsed after thecutting. The first and second detector means are located so as tosatisfy the relation that T T, T where T is the time required for onecycle of operation. The cutter means is operated to effect an addi- Vtional cutting operation when the first detector means properly operatesbut the second detector means does not do so,

6 Claims, 11 Drawing Figures PATENTEDJuumwu v 3Q 8l7l134 men n or 4,

FIG. 7

sws sws L 6 sm a b 0 ob vonb-I/ BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to a roll cutting device incopiers, printers or the like which employ a rolled printing medium, andmore particularly to a roll cutting device which can detect anyunsuccessful cutting operation and can correspondingly accomplishadditional cutter operations.

2. Description of the Prior Art In a copying machine or the like using aroll of copying medium, it is usually the practice to set apredetermined format of medium (such as format A or B), then select apredetermined length and operate a cutter in accordance with a signalrepresenting the selected length to cut the medium into thepredetermined length, thereafter convey the cut medium to a subsequentprocess station. The cutter operation is stable for restricted types ofthe medium and under restricted ambient conditions, whereas if the types(especially, thickness) of the medium and the ambient conditions(especially, high humidity) are varied, cutting errors would inevitablyoccur with an increasing wear of the cutter edge. Moreover, unsuccessfulcutting occurring in high-speed copying machines would cause the mediumto be conveyed in the form like a chain or would result in jamming.Especially, in an electrophotographic copying machine which generallyincludes heating means for fixing a formed image on the medium at thelast stage of the process, the medium stopped in the heating means wouldlead to a danger of firing and, if the medium is continuous in the formof a chain, it would impart damages to the apparatus itself.

SUMMARY OF THE INVENTION The present invention provides a device whichcan quickly detect any unsuccessful cutting to thereby preventoccurrence of the above-noted possible dangers and further can effect anadditional cutter operation or operations. To achieve this, the presentinvention employs a second detector switch provided in the path of acopying medium rearwardly of the cutter and operated by the copyingmedium in a time T after a cutting BRIEF DESCRIPTION OF THE DRAWINGS Theinvention will become fully apparent from the following detaileddescription thereof taken in conjunction with the accompanying drawings,in which:

FIG. I is a schematic representation of an electrophotographic copyingapparatus to which the present invention is applied;

FIG. 2 is a schematic view showing the construction and arrangementaccording to an embodiment of the present invention;

FIGS. 3 (1) and (2) are diagrams of the electric circuits in respectiveembodiments;

FIG. 4 is an elevational view of the drive system therefor;

FIG. 5 is a plan view of the drive system;

FIG. 6 is a front view of another embodiment using a modifiedarrangement of control switches and cams;

FIG. 7 diagrammatically shows the electrical connection of the presentinvention utilizing an electric timer circuit;

FIG. 8 shows the arrangement of the control switches and cams in theFIG. 7 embodiment;

FIG. 9 is a front view of the detector switch;

FIG. 10 is a perspective view of the detector switch; and

FIG. 11 shows a modified form of the detector switch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there isshown an electrophotographic copying apparatus provided with the deviceaccording to an embodiment of the present invention. An originalcarriage l is mounted on top of an apparatus body 24 and supportsthereon an original 0 to be copied. While the original may be scanned inany known manner, the illustrated example employs such a system that afirst mirror 4 and a second and a third mirror 5 and 6 are moved inparallelism to the original carriage l at the speed ratio of l /2whereby the optical path from a lens 7 to the surface of the object mayalways be maintained at a predetermined length. A lamp a forilluminating the object and a reflector 3 are secured to a first mirrorbase 4-1 (FIG. 2) so that the image from the object may be directed viathe mirrors 4, 5, 6 and through the lens 7 and further reflected by astationary mirror 8 for projection upon a photosensitive drum II.

The electrophotographic process illustratively adopted herein isdisclosed in Applicant's Japanese Patent Publications Nos. 239l0/ 1967and 24748/1968. More specifically, the photosensitive drum I1 isrotatably on a horizontal shaft lI-I fixed to the apparatus body, in thedirection of arrow and at a velocity equal to that of the first mirror 4(in the case of l l magnification), and is subjected to corona dischargefrom a charger l0 and thence subjected to simultaneous application ofimage light from the object O and AC corona discharge by a simultaneousexposure and discharge means 9; whereafter the drum 1] is subjected toan overall exposure by a lamp 21 to form thereon an electrostatic latentimage, which is then brought to a developing station 12 and made into avisible dust image by a so-called sleeve type developing device formedby a non-magnetic cylinder containing therein a magnet; thence the dustimage reaches an image transfer station where a web of paper P fed insynchronism with the movement of the dust image on the drum is broughtinto contact with the dust image while a corona is applied from a coronadischarger 14 to the back side of the paper P to transfer the dust imagefrom the drum to the paper P; thereafter the paper P is separated fromthe drum surface by suction force at separator means 13 and conveyed ona belt 18 to pass below a heater 19 for heating and fixing the dustimage on the paper P;

and finally the paper is discharged through a set of discharge rollers22 onto a tray 23.

After the image transfer, the drum 11 reaches cleaner means 20, whoseblade 20-1 of polyurethane rubber or like material wipes the surface ofthe drum to remove any residual toner thereon. The toner thus removed isdischarged in one direction by a discharge screw 20-2 at the lower partof the cleaner.

The transfer paper P may be in the form of a roll 17, from which thepaper is fed by a set of feed rollers 15-1 and further delivered to theimage transfer station by a set of timing rollers in synchronism withthe image on the drum. The web of paper P is then advanced over apredetermined length, whereupon it is cut by a cutter 16.

The present invention is applicable to an apparatus which uses such aroll of paper as described above, and

embodiments thereof are shown in FIGS. 2 and 3.

The web of paper unwound from the roll 17 is first passed over anuncurling roller 15-3, and then passed between feed rollers 15-1 whileth leading edge of the paper is uniformly trimmed by the chuck cutter16, whereupon the paper is temporally stopped there and ready forcopying. Thereafter, for example, in response to a paper feed signalfrom a paper feed start switch SW1 actuated by a cam C3, first the feedrollers 15-1 and then the rollers 15-2 are rotated, the latter being insynchronized relationship with the formed image on the drum, whereby thepaper P is fed while the mirror train in moved horizontally (leftwardlyin the drawing) in response to a signal from a print button or the likeprovided separately.

, The drive system for the mirror train is shown in FIGS. 4 and 5. Thefirst mirror base 4-1 and the second mirror base -1 are journalled forsmooth movement on rails 25 each fixed to the apparatus body 24. Adriving wire 36 has one end thereof secured to the appara tus body at apointC and extends via a pulley 39 rotatably mounted on the secondmirror base 5-1 by means of a shaft 40, and via a pulley 38 journalledto the apparatus body, and is wrapped for several turns about a drivepulley 31, wherefrom the wire 36 extends in a cross fashion and passesover a pulley 37 and said pulley 39 to an opposite point D, where theother end of the wire is secured to the apparatus body. A point E on thefirst mirror base 4-1 is connected to the wire 36. Thus, when the wire36 is driven at a velocity V in the direction of arrow, the first mirrorbase 4-1 (i.e. mirror 4) is driven at the same velocity V, followed bythe leftward movement of the second and third mirrors 5 and 6 at thespeed of V/2 due to the principle of the running block.

FIG. 5 schematically shows a top plan view of the driven system. Thedrive from motor M istransmitted via gears 29 and 28 to the drum 11 andfurther to gears 30 and 32. When a clutch CLr-l is electricallyoperated, the mirror train driving pulley 31 is driven through gears 29,30, clutch CL-l and shaft 41 in the direction of arrow indicated in FIG.4, thus moving the mirrors leftwardly at the velocity V. Next, when theclutch CL-l is disconnected and the clutch CL-2 is operated, the shaft41 and pulley 31 are reversely driven through gears 29, 30, 32, clutchCL-2, sprocket 34, chain 35 and sprocket 33, at a velocity V determinedby the gear ratio, thus reverting the mirrors rightwardly.

In the electric circuit shown in FIG. 3, a stop switch SW4 and areversing switch SW5 are operated by an actuator 27 provided beneath thefirst mirror base 4-1. In the normal stop position (rightmost endposition) of FIG. 4, the switch SW4 is opened by the actuator 27 so thatboth clutches CL-] and CL-2 are in their OFF positions. When the printbutton PB is depressed, the clutch CL-l is operated to move the mirrortrain leftwardly as already described, so that the mirror train scansthe object while it directs the object image to the drum 11. When theactuator 27 is disengaged from the stop switch SW4, this switch isclosed to permit the clutch CL-l to continue its operation even if theprint button PB is released.

On the other hand, when the mirror train comes to the leftmost endposition until the actuator 27 is engaged with the reversing switch SW5,the switch SW5 is closed at its contact b to energize a relay RL-A,whose contact a-l and accordingly the clutch CL-l is thus disconnected,whereupon the relay RL-A selfholds by its contact 2-2 and has itscontact a-3 closed, thus operating the clutch CL-2 to return the mirrortrain rightwardly until the actuator 27 opens the stop switch SW4.Thereupon, the relay RL-A and clutch CL-2 are disconnected to completeone cycle. Further, a contact a-S serially connected with the printbutton PB is inserted to release the self-hold of the relay RL-A even ifthe print button PB is depressed inthe open position of the switch SW4.1 In the arrangement described above, a second detector switch SW3 isprovided at an intermediate point between the cutter 16 and the imagetransfer station 14, as shown in FIG. 2. For the purpose ofillustration, let L be the length of the path traversed by the paperfrom the cutter 16 to a point B in the image transfer station, AB be thecircumferential length from the exposure point A on the dru n 11 to thepoint B in the image transfer station. If AB L, it will be possible tooperate a cutter operating solenoid SL concurrently with the operationof the mirror train reversing switch SW5. Thus, the reversing switch SW5can also serve as a cutting command switch SW1.

It will thus be seen that depression of the print button PB closes theclutch CL-l to move the mirror train leftwardly while scanning theobject O and projecting the reflected image thereon upon the drum 11 viamirrors 4, 5, 6, lens 7 and mirror 8, and concurrently therewith, thepaper P is fed in by paper feed rollers 15-1, 15-2. Then the actuator27changes over the reversing switch SW5 to its contact b to disconnectthe clutch CL-l and operate the clutch CL-2, whereby the mirror trainreverses its stroke while the contact a-4 of the relay RL-A is changedover to the contact a to charge a capacitor C, whose charging currentenergizes the solenoid SL to operate the cutter 16 so as to cut thepaper P into a predetermined length. When the paper P is properly cut,the sheet of paper thus cut off will pass by the second detector switchSW3 to change over this switch to its contact b, whereafter the actuator27 opens the stop switch SW4, thus completing one cycle. Thereupon, thecontact a-4 shifts back to its contact b to cause the capacitor C todischarge through a circuit of (SW3-b) (a-4-b) and a resistor R.

However, if the paper cutting is unsuccessful, the paper P will remainastride the cutter 16 so that the paper P is still present on both sidesof the cutter, and thus the second detector switch SW3 is maintainedclosed at the contact SW3-a by the paper to thereby keep the cutterready for an additional cutting opera tion. On the other hand, thedetection of unsuccessful cutting and the additional cutting operationmust take place during one cycle and prior to a subsequent cycle.Therefore, in the case of FIG. 3 (1) for the illustrated embodiment, theswitch SW4 coming to the final position in one cycle is made to act as asecond detector switch for imparting an additional operation command.When the switch SW4 is opened at the final position, the contact a-4 ofthe relay RL-A is connected with the contact b to form a circuit of(a-4b) (SWS-a), through which the capacitor discharges to energize thesolenoid SL and resume the cutting operation.

While in the foregoing the stop switch SW4 has been made to act as afirst detector switch, if it is desired to make the point of detectiontime take place earlier, then a first detector switch SW2 may beprovided at a spatial point corresponding to the time before thereverted mirror train comes to the final position of the stop switchSW4, i.e. at an intermediate point between the switches SW5 and SW4.However, since the return I velocity V of the mirror train is higherthan the normal forward velocity V thereof, the relative positions ofthe switches SW3 and SW2 must be determined so as to satisfy therelation that T T T where T is the time required for the trailing edgeof the paper P to pass through the second detector switch after thereversal of the mirror train, T is the time required for the mirrortrain to pass through the first detector switch SW2, and T is the timerequired for one reciprocal cycle of the mirror train.

The circuit in the case described just above is shown in FIG. 3 (2). Thefirst detector switch SW2 operable in a predetermined time T after acutter operation to start an additional cutting operation of the cutter,and the second detector switch SW3 for detecting whether the paper hasbeen cut properly or not, are set so that they are respectively operatedupon lapse of time T and T after the operation of the cutter and thatthe relation T, T is satisfied, namely, so that the switch SW3 is openedafter the time T T,) when proper cutting has been done. The additionalcutter operation is accomplished with the charge from the capacitor Cbeing supplied to the solenoid SL through the first detector switchSWZ-band the second detector switch SW3-a. It is to be noted that the time Tis constant once the switch positions are determined, whereas the timeT, is variable with the length of the original image (i.e. the length tobe scanned).

In the embodiment described above and shown in FIG. 2, the switch forthe reciprocation of the mirror train and the first detector switch SW4(or SW2) are all disposed in the path of travel of the mirror train, butthe construction and arrangement as shown in FIG. 6 is also feasible.

As shown in FIG. 6, a camming plate 42 rotatable in the direction ofarrow at the velocity equal to the velocity V of the mirror train may bemounted as on a mirror driving pulley shaft 41, and may be provided withcams C1, C2 and C3. Switches SW1, SW2, SW3, SW4 and SW5 may also beprovided. ln scanning an object, some auxiliary running distance 1 isusually necessary to prevent the overshot of velocity arising from theinertia of the mirrors and the like. Therefore, the mirror train travelsover a distance 1 l, which is longer than the actual image length, andaccordingly, the feeding of paper P must start later by 1 than the startof the mirror train. For this purpose, there is provided a paper feedstarting switch SW1. When the cam C3 actuates the switch SW1, the paperfeed is started, and when the cam C3 engages the reversing switch SW5,the clutch CL-l is disconnected but the clutch ClJ-2 is operated and thecutter is operated at the same time. The length of the paper sheet thuscut off is equal to the length of the original image, as is the casewith AB L in FIG. 2. The cam Cl, which serves to actuate the firstdetector switch SW2, is designed so that it is operative in the returnstroke only and not in the forward stroke.

Although the detector switches have been shown as microswitches, theymay alternatively be photodetector switches comprising a combination ofa light source and a photoelectric element.

The above-described embodiments are arranged to accomplish an additionalcutting operation when unsuccessful cutting has been detected, but theremay be such situations that the twice repeated cutting operation is nosufficient to cut the paper.

FIG. 7 shows a multi-cutting system which utilizes a CR timer circuitfor repeating the cutting operation more than twice until the paper iscompletely cut off.

In FIG. 7, the stop switch SW4, when in its normal stop position(rightmost end position), is closed at its contact SW4-a by the actuator27 and both clutches CL-l and CL-2 are disconnected. Depression of theprint button PB energizes a relay RL-C, whose contact C-2 is thusshifted to the contact a to supply the power to the clutch CL1, therebymoving the mirror train leftwardly to scan the object and expose thedrum ll to the object light. When the actuator 27 is disengaged from theswitch SW4, this switch is changed over to the contact SW4-b but therelay RL-C self-holds by its contact Cl, thus permiting the clutch CL-lto continue its operation even if the print button is released.

When the mirror train reaches its leftmost end position so that theactuator 27 engages the switch SW5 to shift the latter to its contactSW5-b, the reversing clutch CL-Z is operated through the relay RL-C withits contact C-l opened, the closed contact C-2-b and closed switchSW4-b, to thereby return the mirror train rightwardly and cause theactuator 27 to bring about the open switch SW4a, thus disconnecting theclutch CL-2 and stopping the mirrr train. Thus, one cycle is completed.

Where the switch SW5 for producing a reversing sig nal is to serve alsoas the cutting command switch, the switch SW5-b is used for the switchSW6d (hereinafter referred to as SW5-d). When the switch SW5-d isclosed, i.e. when the mirror train begins to revert, the cuttingsolenoid SL is operated and by that time, the paper P has already beenadvanced to the point B, i.e. by a length satisfying the relation L AT?in FIG. 2. In this instance, a cutting command switch SW6 operablesimultaneously with the reversing switch SW5 may be provided in themanner as shown in FIG. 6, the switch SW6 serving also as the switchSW5. The arrangement described just above is substantially identical inoperation with the previously described embodiments.

A CR timer circuit is combined with the abovedescribed circuit of thecutting solenoid SL, and such circuit is controlled by the seconddetector switch SW3 in the paper feeding system so that cuttingoperation may be repeated until the web of paper from the supply roll iscompletely severed. As soon as the solenoid SL is operated with theswitch SW-d closed as described above, a relay RL-D is energized througha diode D to close its contact d-l. At that time, the cut paper stillrests on the second detector switch SW3 so that the relay RL-D remainsenergized even if the switch SW5-d is open, but the relay RL-D becomesdeenergized when the leading edge of the paper sheet has passed by theswitch SW3.

If the paper should fail to be cut well and the switch SW3 continues itsclosed position, the relay RL-D will self-hold but will be disconnectedfrom the solenoid SL by the diode D, thus permitting the cutter 16 to bereturned to its initial position by a spring.

As soon as the relay RL-D is energized due to the above-described closedposition of the reversing switch SW5 d, the contact d-2 thereof is opento allow a current to flow to the capacitor C and to the base oftransistor Tr, thusboosting the terminal voltage of the capacitor C andalso boosting the terminal voltage of the relay RL-B in the transistorcircuit. Such voltage boost continues until the second detector switchSW3 is opened (i.e. paper is severed) and the relay RL-D is reset.

If during that while the paper has been severed, the second detectorswitch SW3 will be opened by the trailing edge of the severed papersheet after the aforesaid predetermined time T, has elapsed (T, L/S,where S is the velocity at which the paper is fed), so that the relayRL-D will be reset while the timer circuit is cut off. Thereupon, thecontact d-2 is closed to cause the capacitor C todis charge throughresistor R2.

If the paper could not be severed within the time T, or more, the chargein the capacitor C will boost the maximum terminal voltage V, of theexciting coil of the relay RL-B to a level exceeding its operatingvoltage V,, (the relation V, V,, being determined by the values of VR,R1, R2 and C), thus operating the relay RL-B to close its contact 11-1and energize the cutter operating solenoid SL for an additionaloperation of the cutter Thereupon, the contact 11-2 of the relay RL-B isclosed to cause the capacitor C to discharge its stored charge'throughthe transistor base and resistors R1, R2. When the terminal voltage ofthe relay RL-B becomes lower than its reset voltage V,,, the relay RlJ-Bis reset to open the contact b-l, thus resetting the solenoid SL.Simultaneously therewith, the contact b-2 is also opened so that theterminal voltages of the capacitor C and relay RL-B start to rise.

If the paper has been served successfully by the above-described cutteroperation, the trailing edge of the paper sheet will pass by the switchSW3 during the predetermined time T, after the cutter operation, thusopening the switch SW3 to reset the relay RL-D and close its contactd-2, so that the capacitor C quickly discharges through the resistor R2to cause the relay RL-B to reduce its terminal voltage in preparationfor a subsequent detection. At this time, the values of VR, R1, R2 and Care determined so that the maximum terminal voltage V, of the relayRLl-B, unlike the previous case, is in the relation V V if the timeduring which the contact b-l is closed is TB. Further, by setting theresistance values of R1 and R2 so as to satisfy the relation TB z AT,the relation V, V may be obtained so that the point of time at which thecutter is additionally operated at the time interval T, after one cutteroperation is always identical between a first, a second and subsequentadditional cutting operation, and the values of VR, R1, R2 and C can beso set that the point of time for additional cutter operation comesearlier than in the case where V, V The reason is that when V V, V thepoint of time for a first additional cutter operation is delayed andwhen V, V the point of time for a second additional cutter operation isdelayed.

Next, if the paper still stays on the second detector switch SW3 tomaintain this switch closed even when the time T, has elapsed after theforementioned first additional cutting operation, the terminal voltageof the relay RL-B will rise up to a level exceeding its operatingvoltage, whereupon the relay RL-B will be operated to effect a secondadditional cutting operation until the paper is completely severed. Inthis way, the additional cutting operations may be repeatedautomatically. Further, the contact d-3 of the relay RL-D is inserted inseries with the copy button PB so that when the relay RL-D is being inoperation, ie when the timer circuit for additional operation of thecutter is being in operation,the contact d-3 is opened to inhibit anysubsequent copying operation. It is also possible to incorporate adevice for operating a conventional time limit means by means of therelay RL-D contact so that during anunusually extended operating time ofthe relay RL-D or during successive occurrences of unsuccessful cuttingoperations, the time limit mean produce a signal to operate an indicatormeans such as lamp, buzzer or the like or to stop the paper feed.

FIG. 8 shows a mechanical similar in function to the embodiment of FIG.6 but in which switches SW1, SW4 and SW5 are actuated by the cams C3,C3, and C2 on the camming plate 42.

FIG. 9 shows a specific form of the aforesaid second detector switch.

In a high-speed copying apparatus, paper cutting is usually effectedwithout the paper being stopped. Since the cutter severs the paper webfrom one side edge thereof to the other side edge, the paper unavoidablytends to be cut obliquely with respect to the longitudinal axis thereof.FIG. 9 shows means for preventing such tendeny. In the process from thecutting station 16 via the timing rollers 15-2 to the image transferstation, a U-shaped curve B is provided by a guide plate 48 just beforethe rollers so as to bend the paper P into a U- shape along the innerbottom surface of the guide plate 48 and direct the paper to the timingrollers 15-2.

Concurrently with the signal for cutting the paper P, a brade isimparted to the feed rollers 15-1 to interrupt the paper feedtemporally, whereupon the paper is cut. This ensures straight cutting ofthe paper. Since the timing rollers 15-2 are then in rotation, the paperis drawn somewhat upwardly from the lowest surface of 'the guide bythese rollers, but upon severance the paper settles down at the lowestposition from its own gravity.

If the cutting should be unsuccessful, a preceding sheet of paper willbe drawn by the timing rollers 15-2 because the rollers 15-1 are braked,so that the paper will be tensioned as indicated by dotted line, therebyrotating a detecting lever 44 to cause an actuator 45 at one end of thelever shaft 43 to actuate the second detector switch SW3.

When the paper has been cut off, the tension in the paper is released topermit the detector lever to return to its original position, thusreleasing the switch SW3.

In this instance, the detector lever 44 on the shaft 43 may be in theform of a lever 47 which is integral substantially along the entirewidth of the paper web as shown in FIG. 11 or a plurality of levers 44may be provided in the direction of the paper width, whereby gooddetection may be ensured even if any unsuccessful cutting occurs with anuncut portion left in the side edge or center of the paper web.

We claim:

1. In a copying apparatus or the like using a rolled medium, a devicefor cutting the rolled medium into a predetermined length, said devicecomprising cutter means, cutter operating means, rolled medium conveyormeans and a conveying path both provided rearwardly of cutter means,first detector means operated when a time T, determined by the length ofthe medium cut off has elapsed after the cutting, and second detectormeans operated by said rolled medium when a predetermined time T haselapsed after severance of said rolled medium, said first and seconddetector means being located so as to satisfy the relation that T T, Twhere T is the time required for one cycle of operation, said cuttermeans being caused to effect an additional cutting operation when saidfirst detector means properly operates but said second detector meansdoes not properly operate.

2. A device according to claim I, wherein said cutter operating meansincludes a solenoid and a capacitor serially connected together, saidsolenoid being energized by a charging current flowing through saidcapacitor to effect a rolled medium cutting operation, and when thecutting operation is unsatisfactory, said second detector means detectsit to cause :said solenoid to effect an additional cutting operation.

3. A device according to claim 1, wherein said first detector meansserves also as means for setting the final position of one reciprocalcycle of said copying apparatus or the like.

4. A device according to claim 2, wherein a timer circuit isparallel-connected with said solenoid so that, when a cutting signaldoes not come from said second detector means, first relay meansenergized upon energization of said solenoid continues its ownenergization to thereby charge said capacitor whose charging voltage isapplied to second relay means, and when such condition continues longerthan said predetermined time T said second relay means closes thecircuit of said solenoid to effect a cutter operation, whereupon saidcapacitor, said second relay means, etc. are reset temporally, all theseseries of operations being again repeated in the absence of a rolledmedium cutting signal.

5. A device according to Claim 1, further comprising timing roller means(15-1, 15-2) provided forwardly and rearwardly of said cutter means (16)in said rolled medium conveyor means, a guide portion (E) providedbetween said cutter means (16) and said timing roller means (15-2) tocurve and direct said medium, and third detector means for braking saidtiming roller means (lS-l) during the cutter operation for cutting therolled medium widthwise thereof, to thereby detect that the curvedportion of the rolled medium is tensioned as it is drawn by said timingroller means upon unsuccessful cutting.

6. A device according to claim 5, wherein said third detector meansincludes a detector lever (47) for braking the feed rollers (15-1) justpreceeding the cutter during the cutter operation for cutting the mediumstraightly widthwise thereof, to thereby detect the entire width of themedium tensioned as it is drawn by said timing roller means (15-2) uponunsuccessful cutting, thus detecting a localized failure in cutting themedium.

1. In a copying apparatus or the like using a rolled medium, a devicefor cutting the rolled medium into a predetermined length, said devicecomprising cutter means, cutter operating means, rolled medium conveyormeans and a conveying path both provided rearwardly of cutter means,first detector means operated when a time T1 determined by the length ofthe medium cut off has elapsed after the cutting, and second detectormeans operated by said rolled medium when a predetermined time T2 haselapsed after severance of said rolled medium, said first and seconddetector means being located so as to satisfy the relation that T3 >T1 > T2, where T3 is the time required for one cycle of operation, saidcutter means being caused to effect an additional cutting operation whensaid first detector means properly operates but said second detectormeans does not properly operate.
 2. A device according to claim 1,wherein said cutter operating means includes a solenoid and a capacitorserially connected together, said solenoid being energized by a chargingcurrent flowing through said capacitor to effect a rolled medium cuttingoperation, and when the cutting operation is unsatisfactory, said seconddetector means detects it to cause said solenoid to effect an addiTionalcutting operation.
 3. A device according to claim 1, wherein said firstdetector means serves also as means for setting the final position ofone reciprocal cycle of said copying apparatus or the like.
 4. A deviceaccording to claim 2, wherein a timer circuit is parallel-connected withsaid solenoid so that, when a cutting signal does not come from saidsecond detector means, first relay means energized upon energization ofsaid solenoid continues its own energization to thereby charge saidcapacitor whose charging voltage is applied to second relay means, andwhen such condition continues longer than said predetermined time T2,said second relay means closes the circuit of said solenoid to effect acutter operation, whereupon said capacitor, said second relay means,etc. are reset temporally, all these series of operations being againrepeated in the absence of a rolled medium cutting signal.
 5. A deviceaccording to Claim 1, further comprising timing roller means (15-1,15-2) provided forwardly and rearwardly of said cutter means (16) insaid rolled medium conveyor means, a guide portion (E) provided betweensaid cutter means (16) and said timing roller means (15-2) to curve anddirect said medium, and third detector means for braking said timingroller means (15-1) during the cutter operation for cutting the rolledmedium widthwise thereof, to thereby detect that the curved portion ofthe rolled medium is tensioned as it is drawn by said timing rollermeans upon unsuccessful cutting.
 6. A device according to claim 5,wherein said third detector means includes a detector lever (47) forbraking the feed rollers (15-1) just preceeding the cutter during thecutter operation for cutting the medium straightly widthwise thereof, tothereby detect the entire width of the medium tensioned as it is drawnby said timing roller means (15-2) upon unsuccessful cutting, thusdetecting a localized failure in cutting the medium.